Winter is almost officially here and with it snow and ice! One of my favorite things is seeing the trees covered in snow, especially deciduous trees with snow delicately sitting on their bare branches. Evergreen branches weighed down look like frosted gingerbread trees. It is calm and quiet with sounds in the forest muffled by snow. I have to wonder though: what are the impacts of snow on the trees?
The snow has both benefits and drawbacks for trees. The snow on the ground keeps the roots insulated from extreme fluctuations in temperatures, which can cause heaves in the ground and which can damage roots. In addition to fluctuations in temperatures, snow protects the roots from extremely low temperatures that can have adverse effects on root systems. In the spring as snow melts, it provides water for the soil and fresh growth.
The snow also has some negative effects on trees and woody plants. The buildup of snow can weigh down branches causing bends, breaks, splits, and can cause them to fall or uproot. Coniferous evergreens (such as pines and firs) can handle more weight than a broadleaf evergreen (such as boxwoods and holly). Some of the first trees to experience breaking branches are willows and red and silver maples because they are weak-wooded trees. Branches that grow at a right angle from the tree are less likely to break than those growing at tighter angles. The breaking point of vertical branches is met more quickly than that of horizontal branches. Trees with more vertical branches, such as cedars, also collect snow in the nooks of their branches more readily than horizontal branches, which shed the snow. Some trees such as birches can bend all the way to the ground and still manage to recover, although they also can stay bent for years after a heavy snow load.
Keep in mind that there are some benefits to branch breakage; “Nature prunes trees, too. Wet snow may break off small twigs and dead branches. It can do a good job of pruning that way. Just follow up with some cleaning cuts,” says Tchukki Anderson, staff arborist with the Tree Care Industry Association. As Anderson states, it is good to clean up natural branch shedding to ensure the trees heal quickly and aids in prevention of the spread of disease and pests. Preventative measures can also be taken, such as pushing up on the underside of branches to knock the snow off. However, do not push down on top of the branches, as this can cause them to break. As always, be cautious of broken branches falling from the tree. So, as snow is falling don’t forget about your trees; they will thank you in the spring!